The labels on the medical marijuana at one Oakland dispensary include some familiar initials like THC -- the active ingredient that gives users a high. But alongside is another set of initials most people are not familiar with -- CBD, short for cannabidiol.
"In the past few years, numbers of breakthroughs have been made about the chemical compounds in cannabis plant. One of the most important discoveries is of a compound called CBD. CBD is medically very effective, but has no psychoactive effect," Steve DeAngelo said.
DeAngleo runs the Harborside Health Center medical marijuana dispensary. He says a small, but growing number of scientists are exploring the uses of non-psychoactive CBD.
Some early research suggests the molecule could have benefits for fighting inflammation and muscle pain.
If CBD has flown under the radar, it may be because growers were not looking for it.
"Unfortunately, all of the CBD has been removed from the cannabis supply in California," DeAngelo said. "The reason for that is in underground market, psychoactivity was the most desirable trait, anything not psychoactive was selected out by breeders."
Now growers for Harborside have begun identifying and cultivating marijuana strains that are high in CBD, and in many cases, low in THC.
"So it offers an option to patients who are really looking for the medical effect of cannabis and don't desire any of the psychoactivity," DeAngelo said.
The idea of medical marijuana without the kick has also caught the eye of the pharmaceutical industry.
A British pharmaceutical company has just been given the go-ahead to market a cannabis spray in England called Sativex, based on a formula heavy in CBD.
"So it takes the whole plant it removes the active components, then there's some of manipulation of the ratio of CBD to delta-9 THC, which makes it more pharmacologic," Dr. Donald Abrams said.
Abrams is head of Hematology-Oncology at San Francisco General Hospital and a long time cannabis researcher at UCSF. He says while promising, CBD-based therapy by itself is still unproven.
"I don't think we know because clinical trials have not really been done looking at CBD alone," Abrams said.
Still, interest in less potent forms of medical marijuana is growing, along with the drug's expanding use in treatment.
In blinded clinical trials at UC Davis, Dr. Barth Wilsey compared marijuana containing lower amounts of THC (the compound that produces the high) to samples with higher amounts. He found both, when inhaled through a vaporizer, were similarly effective at treating chronic pain in certain categories of patients.
"We're trying to find the lowest dose, so that it's not diverted to the recreational user," Wilsey said.
At the Harborside dispensary in Oakland, DeAngelo believes locally grown, low dose products can successfully compete with versions under development by pharmaceutical companies.
"We have all the expertise that's required to deliver this product to patients in a good way," DeAngelo said.
Written and produced Tim Didion